Topics - asfarley

We're using NHD-2.4-240320CF-CSXN#-F on a new product. I'm just getting started writing the basic driver.

I'm experimenting with writing solid R/G/B blocks to the screen, and I've noticed a few strange effects:

* If I fill the entire screen with red or green, it works as expected; if I attempt to fill the entire screen with blue in one shot, the end result is a flashing white image * If I fill the screen incrementally with blue (in full-screen-width, 10-pixel-high blocks, step-by-step) then the screen appears completely blue, as expected * If I fill the screen with blocks in the order R/G/B (1/3 of the screen is red, 1/3 is green, 1/3 is blue) then I get the flashing-white-screen effect * If I fill in the order B/G/R, then I get the correct image * Most of the time, while the write operation is in progress, the entire image flashes white * I have seen some instances where the screen did not flash white between write operations; not sure what was different in that scenario

Are these phenomena familiar to anyone here?

It feels a bit like blue pixels consume more power, and I'm running into a power-stability issue by setting the entire image blue in one-shot, whereas maybe incremently updating to a 100%-blue image is easier on the power supply. Is that possible? Or is something else going on here?

I'm working with an OLED module for a new product. Previously, we used the module NHD-0216MW-SB3 which doesn't include a contrast resistor setting. In our new layout, we use NHD-0216MW-AB3 which doesn't have the same peripheral circuitry as the NHD-0216MW-SB3 module. The display is being used in SPI mode.

The display isn't responding to commands. I believe the SPI commands are correct because they worked on the previous module; both devices use the US2066 internally and they're both running on low-voltage IO logic.

Measuring on IREF, there is no voltage. All the other pins on the OLED module look correct. Here's what I've measured on a multimeter: